SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2baf1048550266f2fe302c07ed458659858e8c4952868ed37e9231da51892baa' 
  AND token = 'L9o1AVUh1tCeYPKdKPQasHckcdw5mywvUaZqxaUZ0Sw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}